@import url('https://fonts.googleapis.com/css?family=Poppins:100,200,300,400,500,600,700,800,900');
body
{
    margin: 0;
    padding: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background: #060c21;
    font-family: 'Poppins',sans-serif;
}
.box{
    position: relative;
    width: 350px;
    height: 450px;
    display: flex;
    justify-content: center;
    align-items: center;
    background: #060c21;
}
.box:before
{
    content: '';
    position: absolute;
    top: -2px;
    left: -2px;
    right: -2px;
    bottom: -2px;
    background: #fff;
    z-index: -1;
}
.box:after
{
    content: '';
    position: absolute;
    top: -2px;
    left: -2px;
    right: -2px;
    bottom: -2px;
    background: #fff;
    z-index: -2;
    filter: blur(40px);
}
.box:before,
.box:after
{
    background: linear-gradient(235deg,#89ff00,#060c21,#00bcd4);
}
.content
{
    padding: 20px;
    
    color: #fff;
}